Apparatus for cracking hydrocarbons



J. W. COAST, JR.

APPARATUS FOR CRACKING HYDROCARBONS.

APPLICATION FILED MAR. 22. 1917.

1 34 5, 1 33 1 v Patented June 29, 1920.

cawanwwrr j, Wm

UNITED STATES PATENT" OFFICE.

JOHN W. COAST, JR., 0F TULSA, OKLAHOMA, ASSIGNOR TO THE PROCESS COMPANY, A CORPORATION OF MARYLAND.

APPARATUS FOR CRACKING I-IYDROGARBON'S.

Specification of Letters Yatent.

Patented June 29, 1920.

Application filed March 22, 1917. Serial No. 156,653.

ing drawings, forming a part of this specification.

My invention relates to improvements in apparatus for cracking petroleum hydrocarbons, one of-the objects being to protect cracking stills from the injurious effects of coke-forming substances which tend to accumulate on the hottest parts of the stills. This feature of the invention increases the efficiency of the cracking apparatus by circulating the coke or carbon away from the point at which heat is transmitted to the still, thus permitting the heat to be trans mitted freely from the still to the oil, at the same time avoiding the danger of overheating the metal of the still, and allowing the apparatus to remain in service for a considerable period of time without removing the coke.

Another object is to increase the efiiciency of the apparatus by forcibly circulating the relatively cool liquid to the hottest part of the still. A further object is to increase the yield by compressing gas and forcing it into the liquid contents of the still. This gas is preferably a product of distillation. recovered from the'condenser of a cracking apparatus.

In the preferred form of the invention all of the foregoing-objects are attained by conducting gas from the condenser .to which the cracking still is connected, compressing such gas and forcing it into the liquid contents of the still.

Figure I is a diagrammatical view of a cracking apparatus'embodying the features of my invention.

Fig. II is an enlarged transverse section of thestill taken on the line *II--II, Fig. I.

Fig. III is an enlarged fragmentary view showing the discharge pipes at the lower portion of the still.

To illustrate the invention, I have shown a still 1 arranged above a heating chamber 2, and connected by means of an air cooled 7 end of the still to the other.

vapor pipe 3 to a reflux condenser 4. 5 designates a vapor pipe leading from the reflux condenser to a main condensing coil 6, from which the low boiling point product is conducted through a pipe 7 and into a receiving tank.8. The condensing coil 6 is preferably arranged'in a water tank 9. The air cooled vapor pipe 3 constitutes a reflux condenser, and it is inclined to allow the condensate to flow backwardly to the still.

The apparatus I have shown is particularly adapted for use in cracking high boiling point products of distillation, such, for example, as the distillates or residues resulting from the distillation of petroleum. The oil'to be treated is introduced into the still in any suitable manner, and any desired ressure may be obtained by regulating the valve 10, preferably located in the vapor pipe 5. The pressure in the still, vapor pipe 3 and reflux condenser 4, is preferably greater than fifty pounds per square inch, and the temperature of the contents of the still preferably ranges from about 600 F. to 800 F. If the pressure regulating valve 10 is arranged in the Vapor line as herein shown, the contents of the still will-be maintained 'under the desired high pressure, and the contents of the condenser 6 will be maintained under a pressure of about one atmosphere.

A trap, or liquid seal'll, is formed in the condensate pipe 7 to prevent the gas from passin to the receiving tank. 8. This gas is pre erably conducted through a pipe 12- and utilized to accomplish several desirable results, as will be hereinafter pointed out.

13 designates a coke trap or catch basin, preferably in the form of a false bottom arranged in the lower portion of the still and extending from one end of the still to the other. ranged within the still below the false bottom' 13, are provided with transverse discharge ports 16. These discharge pipes are arranged longitudinally of the still and they preferably extend approximately from one The discharge ports 16 are so formed that the fluid discharged therefrom will flow from the still bottom in opposite directions. A conductor 17, leading from a compressor 18, is provided with branch pipes 14 and 15 for conducting fluid to the discharge pipes 14 Discharge pipes 14 and 15, ar-

still, thus causing the coke-forming substance to flow transversely of the arcuate bottom of the horizontal cylindrical still, whereby itis deflected over the upturned longitudinal margins of the false bottom 13. The direction of flow may be reversed by shutting off the supply of fluid to the pipe 14, and permitting the fluid to flow through the pipe 15. By circulating the liquid in this manner I prevent the coke from ac-- cumulating at the hottest part of the still, at the same time forciblycirculating the relatively cool portions of the liquid to the hot still bottom.

In the preferred form of the invention, I utilize a gas for circulating the liquid con-. tents of the still, and this gas is preferably a product of distillation resulting from a cracking process. This may be conveniently accomplished by conducting gas from the-condensate pipe 7, through the pipe 12, into a pump 20, and thence through a conductor 21 to the compressor 18, whereby it is compressed and forced into the lower portion of the still. By recovering the gas in this manner, compressing it, and forcing it into the liquid in the still, I increase the yield of low boiling point hydrocarbons, a large percentage of the gas being absorbed to form part of the low boiling point product.

I claim:

1. In an apparatus for cracking'petroleum hydrocarbons, a cracking still, a condenser connected thereto, means for transmitting heat to the bottom of said still, a coke receiver in the form of a false bottom extending approximately from one end of the still to the other, discharge pipes arranged within the still below said coke receiver, said discharge pipes being arranged longitudinally of the still and provided with transverse discharge ports for the discharge of streams of fluid in opposite directions under said coke receiver, means for forcing fluid through said discharge pipes, and means for regulating the flow of fluid to the different discharge pipes so that the fluid can be discharged alternately in opposite directions.

2. In an apparatus for cracking petroleum hydrocarbons, a horizontal cylindrical cracking still, a condenser connected there to, means for heating the arcuate bottom of said still, a coke trap located within said still and separated from the arcuate bottom thereof, a discharge member located within said still between said arcuate bottom and the coke trap, and means for forcing fluid through said discharge member so as to cir-' culate coke-forming substance transversely of said arcuate bottom and into said coke trap, said coke trap being in the form of a false bottom extending approximately from one end of the still to the other and providedwith upturned longitudinal marginal edges over which the coke-forming substance is deflected by the fluid discharged across said v arcuate bottom.

In testimony that I claim the foregoing I hereunto affix my signature.

JOHN W. COAST, JR. 

